Learning to love mothballs

Today, I learned about the existence of a bacterial species named Polaromonas naphthalenivorans. This lil' guy* fits into the mysterious, often baffling category of extremophile bacteria - that is, species capable of living in environments we normally wouldn't consider habitable. Originally isolated from a coal-tar-contaminated aquifer somewhere in the northeastern US,** P. naphthalenivorans can grow using naphthalene as its only carbon source. It's not terribly surprising, as naphthalene is a major component of coal tar (and was originally isolated from coal tar, in fact), so this species is just working with what it has. It's still rather odd as naphthalene is toxic and a suspected carcinogen. Those kind of rules don't always apply to bacteria.

Dividing P. naphthalenivorans cells. Micrograph is from the Joint Genome Institute (JGI). See this page for more details.

Most people are familiar with naphthalene as a component of mothballs. This paper suggests that a whole metabolic community could subsist on naphthalene, or at least could adapt to its presence. Evolution is great that way!

*Literary anthropomorphism is a constant danger when discussing animals and especially when discussing microbes since it's difficult to understand why they do what they do. I will rarely, however, avoid an opportunity to make bacteria seem cute. They're already tiny, and tiny things are cute, right?

**A paper describing the aquifer describes it using little more detail than "A single truckload of coal tar was buried in a forested area in the northeastern United States." This MicrobeWiki page says it's in South Glens Falls, New York. There's a lab at Cornell that likes to work there. As far as they know, the local drinking water isn't contaminated with coal tar or anything like that.